I worked at a company once that had a subset of employees that were very devout Christians. They would get together before lunch for prayer and that sort of thing, were friendly and welcoming but they never pushed it on anyone else and really didn't talk about it unless someone else raised the subject. They were all smart and got things done and it wasn't a problem.
Honestly your comment sounds very similar to what people say about working with any cultural or racial group they are biased against.
On the other hand I have experienced obnoxious religious people at work (certainly not most religious people of course). They wanted to make a big production and drama about their beliefs and still others wanted to evangelize on the sly. I don't know if it's coincidence, but the "excessively public" religious people to whom I'm referring (more than one workplace and incident) were one and all very poor workers.
Honestly your comment sounds very similar to what people say about working with any cultural or racial group they are biased against.